imshow, imcrop and imread to set a predefined coordinate system to analyze images

Hello,

I have a code shown below that analyzes images to quantify a predefined value termed CTR (basically how bright something is against a background)... I want to set a predefined coordinate system instead of always having to select the area to analyze in each image when I have +50 images. I was wondering what I would need to do to make this adjustment and if anyone had any advice on how to do this.

The code is seen below:

close all clear all

%Images should be labled X.jpg, where X is an integer from 1 to Npics. %Enter number of images to be analyzed.

Npics = 46;

pic = [1:1:Npics]; for n = 1:1:Npics

    I = imread(num2str(pic(n)),'jpg');
    G = rgb2gray(I);
    figure(1),imshow(G),title(['Press enter to crop TISSUE section ',num2str(n)]);
    pause;
    GT = imcrop(G);
    M = mean(mean(GT));
    figure(1),imshow(G),title(['Press enter to crop CONTRAST section ',num2str(n)]);
    pause;
    GC = imcrop(G);
    C = mean(mean(GC));

    mat(n,1) = M;
    mat(n,2) = C;

    for k = size(mat,1)

        CTR(k) = 20.*log10(mat(k,2)./mat(k,1));

    end

end

close all

Answer 1

[Jean-Marie Sainthillier]

For the first image use :

[GT,rec] = imcrop(G);

(rec is a 4-element vector with the form [XMIN YMIN WIDTH HEIGHT])

For others images, you can re-use directly (non-interactively) theses coordinates with :

GC = imcrop(G,rec);